Investigating the Real Air Pollution Exchange at Urban Sites Based on Time Variation of Columnar Content of the Components     

B��lint Alf?ldy  Roland Steib 《Water, air, and soil pollution》2011,220(1-4):9-21

As a new approach, urban air pollution was characterised by the variation of columnar content of the pollutants. Columnar content (CC) was estimated as the product of the pollutant??s mixing ratio and the mixing height. Mixing ratio data of the Metropolitan Air Quality Monitoring Network of Budapest were used, whilst mixing height was calculated by the meteorological AERMET model code. Time variation of CC refers to the real pollution exchange in the atmosphere that allows direct investigation of the emissions as well as post-emission modifications of the pollutants (such as chemical degradation or production). The diurnal urban CO cycle was found to be determined by two or three main influx peaks according to the traffic pattern of the site. The diurnal variation of NO _x level was found to be driven by traffic emission as well. Variant ratios of NO _x to CO influxes obtained for the different locations of the city range from 0.12 to 0.23, probably according to the vehicle composition of the traffic. The daily balance of photochemical production, chemical degradation and deposition of ozone yielded negative or positive depending on the location. Negative balances imply that the polluted urban atmosphere is a net ozone neutraliser source. Entrainment from the free troposphere yielded the major contributor to the diurnal ozone level at each site. The diurnal urban PM₁₀ cycle was found to be determined by traffic emission during the morning and evening rush hours whilst secondary aerosol formation around noon. In the evening, high PM₁₀ level rise was observed due to direct traffic emission as well as rapid conversion of the fine aerosol fraction to the coarse fraction.  相似文献   

Corrigendum to “Hidden, abiotic CO₂ flows and gaseous reservoirs in the terrestrial carbon cycle: Review and perspectives” [Agric. Forest Meteorol. 150 (2010) 321-329]     

Penélope Serrano-OrtizMarilyn Roland  Sergio Sanchez-MoralIvan A. Janssens  Francisco Domingo  Yves GoddérisAndrew S. Kowalski 《Agricultural and Forest Meteorology》2011,151(4):529

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AFLP analysis of genetic diversity in leafy kale (<Emphasis Type="Italic">Brassica oleracea</Emphasis> L. convar. <Emphasis Type="Italic">acephala</Emphasis> (DC.) Alef.) landraces,cultivars and wild populations in Europe     

Stina Christensen  Roland von Bothmer  Gert Poulsen  Lorenzo Maggioni  Marianne Phillip  Bente Anni Andersen  Rikke Bagger Jørgensen 《Genetic Resources and Crop Evolution》2011,58(5):657-666

AFLP markers were used to characterize diversity and asses the genetic structure among 17 accessions of kale landraces, cultivars and wild populations from Europe. The range of average gene diversity in accessions was 0.11–0.27. Several landraces showed higher levels of diversity than the wild populations and one cultivar had the lowest diversity measures. The landraces that were most genetically diverse were from areas where kales are known to be extensively grown, suggesting in situ conservation in these areas as a supplement to storage of seeds in gene banks. An analysis of molecular variance (AMOVA) showed that 62% of the total variation was found within accessions. For most accessions, genetic distance was not related to geographic distance. Similarities among accessions were probably not caused by recent gene flow since they were widely separated geographically; more likely the relationship among them is due to seed dispersal through human interactions. Our results indicate that a kale population found in a natural habitat in Denmark was probably not truly wild but most likely an escape from a cultivated Danish kale that had subsequently become naturalized.  相似文献   

Interaction of Bordetella bronchiseptica, Pasteurella multocida, and fumonisin B1 in the porcine respiratory tract as studied by computed tomography     

Pósa R  Donkó T  Bogner P  Kovács M  Repa I  Magyar T 《Canadian journal of veterinary research》2011,75(3):176-182

The interaction of Bordetella bronchiseptica, toxigenic Pasteurella multocida serotype D, and the mycotoxin fumonisin B(1) (FB(1)) was studied. On day 0 of the experiment, 28 artificially reared 3-day-old piglets were divided into 4 groups (n = 7 each): a control group (A), a group fed FB(1) toxin (B), a group infected with the 2 pathogens (C), and a group infected with the 2 pathogens and fed FB(1) toxin (D). The B. bronchiseptica infection [with 10(6) colony-forming units (CFU)/mL] was performed on day 4 and the P. multocida infection (with 10(8) CFU/mL) on day 16. From day 16 a Fusarium verticillioides fungal culture (dietary FB(1) toxin content 10 mg/kg) was mixed into the feed of groups B and D. In groups C and D, clinical signs including mild serous nasal discharge, sneezing, panting, and hoarseness appeared from day 4, and then from day 16 some piglets had coughing and dyspnea as well. Computed tomography (CT) performed on day 16 demonstrated lung lesions attributable to colonization by B. bronchiseptica in the infected groups. By day 25 the number of piglets exhibiting lesions had increased, and the lesions appeared as well-circumscribed, focal changes characterized by a strong density increase in the affected areas of the lungs. The gross pathological findings confirmed the results obtained by CT. These results indicate that, when combined with dual infection by B. bronchiseptica and P. multocida, dietary exposure of pigs to FB(1) toxin raises the risk of pneumonia and increases the extent and severity of the pathological changes.  相似文献   

Evaluation of a Rapid Method for the Determination of Urea in Cow’S Milk     

Roland Oltner  Lars-Oue Sjaunja 《Acta veterinaria Scandinavica》1982,23(1):39

A rapid method for the determination of urea in milk was evaluated. The method employed was a urease/glutamate dehydrogenase procedure where the decrease in absorbante of NADH is monitored spectrophotometrically at 340 nm. The repeatability expressed as a coefficient of variation, was 1.4 % and 0.8 % for whole milk and skim milk, respectively. The accuracy of the method for urea determinations in whole milk was satisfactory (coefficient of variation, 2.6 %). Adding the preservative bronopol (0.02%) to the milk or freezing of the milk samples for one week did not alter urea levels significantly (P > 0.05). The storage of preserved whole milk in a refrigerator for 14 days, however, increased milk urea levels measured by 3.1 % (P < 0.001).It was concluded that the method evaluated is simple, rapid (40–50 samples/h) and yields reliable results also when whole milk is used. Since the determination of milk urea may be useful in assessing the feeding of energy and protein, the method is suitable for integration in the existing milk recording system in Sweden.  相似文献   

Two-dimensional simulation of airflow and carbon dioxide transport over a forested mountain: Part II. Carbon dioxide budget analysis and advection effects   总被引：2，自引：0，他引：2  

Haizhen Sun  Terry L. Clark  Roland B. Stull  T. Andrew Black 《Agricultural and Forest Meteorology》2006,140(1-4):352

We apply a high-resolution atmospheric model to assess the influence of mesoscale advection of CO₂ on the estimation of net ecosystem exchange (NEE) using eddy-covariance CO₂ flux measurements at a Fluxnet-Canada forest site located on sloping terrain on Vancouver Island, Canada. The numerical simulation is performed for fair-weather conditions over an idealized two-dimensional mountain bounded by water. The model is enhanced to include a CO₂ budget with a treatment of canopy photosynthesis and soil respiration.The simulation captures the transport of CO₂ by nocturnal drainage flows and weak land breezes. The resulting vertical profiles and time evolution of CO₂ concentration show a significant variation near the ground, associated with stability changes in the atmospheric boundary layer. The simulated vertical CO₂ gradients are found to be large around sunset and sunrise. The decrease of CO₂ concentration over land after midnight and the CO₂ accumulation over the neighboring water surface indicate CO₂ advection.A CO₂ budget analysis of the numerical-model output shows that the mean horizontal and vertical advection have significant fluctuations and opposite signs during daytime, with the net result that they largely counteract each other. At night, mean advection results in the underestimation by 20% of the nocturnal respiration. The estimated NEE at night is dominated by sub-grid-scale vertical flux in this simulation. Further evaluation using 3D simulations with higher resolution is needed to see if our results hold where vertical fluxes are much better resolved.  相似文献   

Economic equilibrium in the Westland: An experimental analysis     

Roger Roland  Westwell Folley 《Scientia Horticulturae》1975,3(1):29-44

The conditions prescribed in economic theory for “equilibrium” in an industry are “normal” earnings for those engaged. That best-known area of intensive horticulture, the Westland in South Holland, reached approximate economic equilibrium in 1971. Not all the constituent sectors of the industry were in mutual equilibrium, and to remain in overall equilibrium few additional resources will be permissible, although output must continue to increase relative to input.In the past such normal earnings are believed to have stimulated producers to further, unjustified expansion. Under current conditions Westland producers will be spared the consequences of unjustified response, because they will need to concentrate upon avoiding the trap of excess capacity. The purchasing power of their most important crop, tomatoes, being now seriously and progressively reduced, rationalization of production under glass is necessary and this is a difficult enough exercise in itself.  相似文献   

Setting New Immunobiological Parameters in the Hamster Model of Visceral Leishmaniasis for <Emphasis Type="Italic">In Vivo</Emphasis> Testing of Antileishmanial Compounds     

Dea-Ayuela MA  Rama-Iñiguez S  Alunda JM  Bolás-Fernandez F 《Veterinary research communications》2007,31(6):703-717

To establish suitable immunobiological parameters for in vivo testing of new antileishmanial compounds in the golden hamster model of visceral leishmaniasis, two groups of 8 animals were infected each with 10⁵ or 10⁷ stationary promastigotes by the intracardiac route and the clinical and immunoparasitological features were monitored up to day 155 after infection. All animals became infected at both doses, although significant differences were observed between parasite burdens in liver and spleen. The mean number of parasites in animals infected with 10⁷ promastigotes increased by 9.5 times in liver and by 43.1 times in spleen compared with those infected with 10⁵ promastigotes. In animals given the higher dose, the outcome of the disease occurred between days 75 and 90 after infection, whereas no signs of disease were apparent in those given the lower infecting dose. Positive antibody (IgG) responses were detected earlier (week 5–7 after infection) in animals infected with the higher dose than in those infected with the lower dose (week 8–10 after infection), but these responses did not correlate with individual parasitological loads in liver and spleen. An inverse correlation was observed between infecting doses and in vitro spleen lymphocyte proliferation against mitogens (ConA). The proportion of CD4⁺ and CD19⁺ spleen cell increased in animals given the higher infection, whereas it decreased in those given the lower infection compared to naive controls.  相似文献   

On-demand canal operation: Optimally designed     

Oulhaj Ahmed  Roland W. Jeppson 《Irrigation and Drainage Systems》1993,7(1):13-27

The design of most canal systems requires that they be operated under rigid schedules, rather thanon-demand. Rigid schedule operation results in water wastage through spillage, or users taking their turn even when the water cannot be efficiently used. This paper develops a two step method for optimally designing a canal system so it can be operated effectively under user on-demand requests for water. The first step determines the cross-sectional dimensions of the canal to provide storage capabilities while minimizing costs, by solving an appropriate nonlinear optimization problem. In the second step a hydraulic simulation model finds a near-optimal storage capacity based on construction and right-of-way costs, penalties due to operational water losses, water over supplied to users and supply shortages. The performance is evaluated by a quality index that is defined as the ratio of volume of satisfied demands to total volume of water requested. Results of regression equations from hundreds of computer sensitivity analyses relating variables are summarized in tables.  相似文献   

Management styles and knowledge cultures, past, present and future, related to multiple-use and urban woodlands     

Anna Jnsson  Roland Gustavsson 《Urban Forestry & Urban Greening》2002,1(1)

This paper is based on interviews with fifteen professionals within ecology, forestry and park and landscape architecture. The interviewees are believed to have had a large influence on woodland planning in Sweden between 1950 and 2000. They have won recognition because of their ability to transform theoretical knowledge into practical action. Their work is translating theory into practice and, as such, it may be regarded as art in its deepest sense. During a long period the educational system as well as the dominating research has been concentrating on providing better facts in a search for the best knowledge, high degrees of generality and objectivity. However, this may cause many disadvantages. It has lead to a standardisation and an oversimplification of knowledge and thereby also to an oversimplification of the landscape. This study is based on a humanistic approach, on theory of knowledge, of how facts coming from the world of natural sciences can be encapsulated in daily woodland management.  相似文献